The present invention relates generally to a data processing system, and more particularly, to a method and apparatus for extracting Web services from resources using a Web services resource programming model.
With Web services, businesses may perform transactions with consumers or other businesses. A service provider may publish available services on the Internet using Web services for an end user to subscribe. For example, a customer may subscribe to obtain stock quotes from a financial institution using Web services.
Web services are provided through a number of standards. An example of a Web services standard is Web Services Description language (WSDL). WSDL, a standard published by the World Wide Web Consortium (W3C), allows a service provider to describe Web services in an extensible markup language (XML) format as a set of endpoints operating on messages. WSDL allows endpoints and messages to be described regardless of the message formats or network protocols.
Another common Web services standard is Universal Description Discovery and Integration (UDDI). UDDI is a standard published by OASIS consortium, which consists of a UDDI community of more than 300 businesses. UDDI provides a platform independent way of describing and discovering Web services and Web service providers. UDDI uses WSDL as interfaces to describe Web services in the registry, for example, a WSDL file may be embedded as a link in a UDDI business service entry. Thus, UDDI is another type of resource within which Web services may be accessible to a user.
In addition to UDDI, other resource models, such as Web services inspection language (WSIL) and discovery of Web services (DISCO), provides other mechanisms for service providers to describe their services and for consumers to discover these services. WSIL allows a service requestor to discover Web services definitions on a Web server, which enables the requestor to easily browse Web servers for Web services.
WSIL is different from UDDI because instead of using a central registry to publish Web services, service providers may provide the service lookup directly on their Web server. When a service requestor makes a request to a service provider for a particular service, the service provider provides a WSIL inspection document that has embedded links that link to other WSIL documents. Each linked WSIL may advertise a different local Web service or a service already described in a UDDI registry. Thus, WSIL allows service providers to organize their services in a hierarchical manner and allows service discovery to be performed in a decentralized manner. Discovery of Web services (DISCO) is similar technology for publishing and discovering Web services provided by Microsoft Corporation. Currently, a service requestor relies on either a uniform resource locator (URL) or a uniform resource identifier (URI) in a Web page to search for a Web service.